Magnetic recording files, such as hard disk drives, are commonly known in the art. Hard disk drives typically employ a plurality of magnetic read/write heads on the end of movable suspension actuator arms to read/write with magnetic disks. Some hard disk drives are required to withstand high G-force impacts and a large number of start/stop cycles. The drives also must unload the heads off the disk surfaces to prevent damage to the system.
One solution to this problem is to provide a off-loading ramp near the outer edge of each of the disks for engaging the actuator arms. Each ramp is positioned so that when the head is moved past the outer diameter of the disk, the head moves off of the disk and onto the stationary ramp. The ramps may be formed from materials which will not shed particles and may be lubricated to prevent ramp wear. The ramps also may have narrow rails formed to reduce static friction and hold the arms in place when they are retracted from the disks.
One prior art device, U.S. Pat. No. 5,408,375, provides a ramp with a cam surface or detent to retain the arm after it is retracted. The ramp has a groove on an opposite side of the detent adjacent to the holding position of the arm when it is retracted. The groove is provided for containing a lubricant which lubricates the arm each time it is retracted. When the arm moves the head back onto the disk, the ramp is lubricated to reduce wear. Although this design is workable, the ramp does not require lubrication for every arm retraction. Excessive lubrication of the ramp causes the lubricant to overmigrate, which can interfere with the operation of or damage the hard disk drive. An improved ramp design with selective lubrication capability is needed.